Advances in technology have resulted in smaller and more powerful personal computing devices. While reducing power consumption, the associated reduction of transistor size and operating voltages also increases sensitivity to noise and to manufacturing process variations.
Such advances present challenges to achieving correct operation of static random access memory (SRAM) under varying conditions. An SRAM cell should be stable enough to be read without changing the data in the cell. Static noise margin is a measure of the read stability of the cell. The static noise margin is the amount of noise that can be imposed on the internal nodes of the SRAM cell before the cell changes its state. The ability to accurately estimate static noise margin is useful in the SRAM design process.